"We'd just like to know what you were doing on those dates."

"Well, I was here. I mean, I haven't left Scotland, I haven't been anywhere near London, or… I haven't been down south for nearly a year."

The inspector smiles thinly.

"Okay, look," I say. "I'd have to check in my diary."

"Could you fetch your diary, Mr Colley?"

"Well, I say my diary; it's in my lap-top. My computer."

"Ah, so you do have one of those. Is that in the building?"

"Yeah. It's downstairs. I just got a new one but all the files are transferred. I'll —»

I start to stand, but the inspector holds up one hand. "Let Sergeant Flavell do that, eh?"

"All right." I sit down again, and nod. "It's on my desk," I tell the sergeant as he goes to the door.

The inspector sits back in his seat and takes out his B&H packet. He sees me watching him again and waves the packet at me. "Sure you won't —?" he asks.

"Um, yeah, I will, thanks," I say, reaching out to take the cigarette and hating myself as I do it but thinking, Christ, these are exceptional circumstances here; I need all the help I can get; every prop counts.

The inspector lights my cigarette and then stands up and walks to the windows facing out towards Princes Street. I turn in my seat to watch him. It's a blustery day; cloud-shadows and patches of golden sunshine slide quickly over the face of the city, turning the buildings to dark then shining grey.

"Lovely view from here, isn't it?" the inspector says.

"Yeah, great," I say. I'm getting a fairly decent hit from the cigarette. I should give up more often.

"Dare say they don't use this room much."

"No. No, I don't think they do."

"Shame, really."

"Yes."

"Funny thing, you know," the inspector says, peering out over the city to the distant fields of Fife, grey-green under heavier clouds on the far side of the river. "The night Sir Toby was killed, and the morning after Mr Persimmon was found, somebody rang up The Times and claimed they were IRA attacks."

The inspector turns to look at me, face wreathed in smoke.

"Yes, well," I say, "I heard the IRA claimed they killed Sir Toby, but then retracted."

"Yes," the inspector says, looking, seemingly puzzled, at his cigarette. "Whoever it was used the same IRA code-word both times."

"Oh?"

"Yes; that's what's funny, you see, Mr Colley. You and me, we both know there are code-words the IRA use when they phone in a bomb warning or take responsibility for a murder or some other crime. You have to have these codes or otherwise any Tom, Dick or Paddy could call in and claim they were the IRA; close down London, they could, first time. But our murderer… he knew one of the code-words. A recent one."

"Uh-huh." I'm feeling cold again. I can see where this is leading. Brazen it out. "So, what?" I say, pulling on my fag, eyes narrowing. "You suspect an ex-policeman, yeah?"

I am favoured with the inspector's thin smile again. He makes that funny sucking noise with his saliva and moves towards me and I have to lean to one side to make way for him. He reaches past me, flicking some ash into the ashtray, then steps back to the window. "That's right, Mr Colley. We did think of a policeman, serving or not." The DI looks like he is thinking. "Or a telephone operator, I suppose," he says, as though surprising himself.

"Or a journalist?" I suggest, raising my eyebrows.

"Or a journalist," the inspector agrees blandly, leaning back against the window-frame, silhouetted by the bright gleam of rushing cloud outside. "You wouldn't happen to know those codes, would you, Mr Colley?"

"Not off the top of my head, no," I say. "They're kept on the paper's computer system these days, protected by a password. But I do write on defence and security matters, amongst other things, and I do know the password, so I have got access to the codes. I can't prove I don't know what they are, if that's what you're getting at."

"Not really getting at anything, Mr Colley. It's just… interesting."

"Look, Detective Inspector," I say, sighing and putting out my cigarette, "I'm a single man, I live alone, I do a lot of work from home and from… all over Scotland; I phone it into the paper. I'll be honest with you; I really have no idea whether I've got alibis for all those dates or not. Quite possibly I do; I have a lot of professional lunches and dinners and just general meetings, keeping in contact with people; people whose word I think you'd take, like police top brass and lawyers and advocates." It never does any harm to remind an inquisitive cop you know people like those. "But, come on." I laugh lightly, holding my arms out. "I mean, anyway; do I look like a murderer?"

The detective inspector laughs too. "No, you don't, Mr Colley." He draws on the cigarette. "No," he says. He brings the cigarette carefully over to the table, leans past me to fold the stub into the ashtray and says, "I helped interview Dennis Nilsen; remember him, Mr Colley? Guy that killed all those blokes?"

I nod as the DI returns to the window. I don't like the way we're going here.

"Young men, lots of young men; under his floorboards, buried in the garden… bloody football team of stiffs, he had." He looks out the window again, away from me. He shakes his head. "He didn't look like a murderer, either."

The door opens and Sergeant Flavell comes in with my new lap-top. Suddenly I have a bad feeling about all this.

I'm in the bar of the Cafe Royal, through the wall from the restaurant where I had lunch with Y and William last week. Above the noise of the bar's chattering patrons I can hear the distant clanking and clattering of cutlery and crockery coming over the tall partition wall and echoing off the place's high, ornate ceiling. I'm staring at the gallery of the island bar while my pal Al is away having a pee and I'm experiencing an optical illusion or something because things are not right; I can see those bottles on the gallery ahead of me, and I can see their reflections behind them, but I can't see me! I can't see my own reflection!.

Al comes back through the throng, politely elbows his way between a couple of people, lifts his coat off his bar stool and leans on the bar beside me, drinking his pint.

"Help me Al," I say. "I'm going crazy or I've become a fucking vampire or something."

Al looks at me. He's older than me — forty-two, I think — mousy hair, teacup-sized bald patch, a couple of fetching parallel scars above his nose that make him look like he's frowning all the time but usually he's laughing, actually. Bit smaller than me. Engineering consultant; met him at one of these stupid paint-ball-guns-in-the-woods boys" games that management tend to think are such a team-spirit-building hoot.

"What are you talking about, you incredible cretin, Colley?"

I nod at the gallery ahead of me. I can see people there, behind the bottles, just as I can see people behind me. I swear they're the same people and I ought to be between them and the mirror behind the bottles but I still can't see myself. I nod again, hoping that the movement will show up in the mirror but it doesn't.

"Look!" I say. "Look: in the mirror!"

It is a mirror, isn't it? I stare. Glass shelves. Brass supports. Bottle of Stoly Red facing me and its back visible in the mirror; likewise a bottle of blue Smirnoff, label facing me and the plain white back of the label visible through the bottle and the vodka inside. Same with the bottle of Bacardi alongside. I can see the little label on the back of the bottle in the mirror, and see it through the bottle from the front. Of course it's a mirror!

Al moves his head so that his chin is on my shoulder. He peers forwards. He takes a pair of glasses I know he's a little sensitive about from his jacket pocket and puts them on.